1. Field of the Invention
The invention relates to a method for the quantitative determination of soldering aid residues, which remain on a workpiece after a preceding processing step, in which the workpiece is acted upon by a fluid. Further, the invention relates to an apparatus which is suitable to a particular degree for carrying out the method. Moreover, the invention relates to a method for dimensioning a workpiece and/or another part.
2. Description of the Background Art
During the processing of workpieces, it is typical in certain processing steps and often also necessary that they be treated with an auxiliary material supporting the processing step. A typical example of this occurs in soldering processes (soft soldering and/or hard soldering processes) and optionally also in welding processes. In this regard, the materials to be connected together are usually treated beforehand with a so-called flux material, which, for example, is sprinkled in the form of a powder on the parts to be connected together, before the actual soldering process (or welding process) is performed. In this case during heating to carry out the soldering process (or the welding process), the flux material causes a cleaning of the part surfaces, so that the finally formed soldered seam (or weld seam) can be made stronger, more durable, and denser.
The use of flux materials in fact proves advantageous during the processing of the workpiece. Typically, the use of flux materials also entails flux material residues on the workpiece and thereby the associated disadvantages. In particular, after the workpiece is finished, soldering agent residues remaining on it can impair the function and durability of other components, working together with the soldered workpiece, and possibly also the workpiece itself, for example, by corrosion. In fact, it is basically possible to remove soldering agent residues from the workpiece after the soldering process has been completed (for example, by washing), but this can prove to be costly and complicated, particularly when the subsequently necessitated drying processes for the workpiece are considered in addition. An apparatus of this type for removing solder residues on objects is described, for example, in DE 38 40 098 C1, which corresponds to U.S. Pat. No. 5,181,648, or in the Japanese patent abstract JP 04172171 AA. Reduction of the amount of the used flux material is also not easily possible, because such a decrease in the flux material amount can entail a worsening of the soldering result, which is likewise undesirable.
The aforementioned problems arise especially to a particular degree when it concerns the processing of workpieces that have especially fine structures and/or especially many curved surfaces (particularly also with small radii of curvature) and in part closed hollow spaces. For example, heat exchangers, particularly heat exchangers for motor vehicles, can be mentioned as examples for workpieces of this type. Because of the varied hollows spaces in such heat exchangers, washing of the heat exchanger after soldering proves to be tedious and problematic. A reduction in the amount of employed flux material is also out of the question, because due to the large proportion of parts to be soldered together the risk of leaking would rise very rapidly to no longer acceptable values.
Another problem occurring in practice is that with the use of soldering aids, particularly of flux materials, empirical values are often drawn upon, when it is a matter of determining the amount of soldering aids to be used during the processing of the workpiece. As a rule, these empirical values are based on the finished soldering result (therefore particularly as to whether or not leaks occur during the soldering process). Because resoldering of workpieces is relatively complicated and expensive, the tendency therefore is to select the amount of the employed soldering aid as higher than the actually necessary amount (this also applies to scrap workpieces). This leads not only to an unnecessarily high consumption of soldering aids (which entails corresponding production costs and environmental pollution unnecessary per se), but also to the situation that the workpiece and other parts, operated together with the workpiece, in a machine are exposed to correspondingly higher wear by the (unnecessarily) high soldering aid residues, and accordingly must be constructed as more durable. This also leads to disadvantages such as particularly cost and weight disadvantages.